Method for decreasing opioid metabolism

ABSTRACT

8-Substituted-2,6-methano-3-benzazocines of general structure I in which A is —CH 2 OH, —CH 2 NH 2 , —NHSO 2 CH 3 , 
                         
Q is O or S and Y is O, S or NOH are useful as analgesics, anti-diarrheal agents, anticonvulsants, antitussives and anti-addiction medications.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.11/205,354, filed Aug. 17, 2005, which was a continuation of U.S.application Ser. No. 10/987,527, filed Nov. 12, 2004, now U.S. Pat. No.7,265,226, which was a continuation of U.S. application Ser. No.10/409,803, filed Apr. 9, 2003, now U.S. Pat. No. 6,887,998, which was adivisional of 10/305,287, filed Nov. 26, 2002, now U.S. Pat. No.6,784,187. U.S. Ser. No. 10/305,287 was a continuation-in-part of PCTInternational Application PCT/US01/045581, filed Oct. 31, 2001, andpublished under PCT Article 21(2) in English as WO 02/36573 on May 10,2002. PCT/US01/045581 claimed benefit from U.S. Provisional Application60/244,438, filed Oct. 31, 2000. The entire contents of each of theprior applications are incorporated herein by reference.

STATEMENT AS TO RIGHTS UNDER FEDERALLY-SPONSORED RESEARCH

This invention was made with Government support under Contract No. R01DA12180, awarded by the National Institutes of Health. Accordingly, theU.S. Government has certain rights in this invention.

FIELD OF THE INVENTION

The invention relates to opioid receptor binding compounds containingcarboxamides, formamides, thiocarboxamides and hydroxyamidines. Thecompounds are useful as analgesics, anti-diarrheal agents,anticonvulsants, antitussives, anti-cocaine, and anti-addictionmedications.

BACKGROUND OF THE INVENTION

Opiates have been the subject of intense research since the isolation ofmorphine in 1805, and thousands of compounds having opiate oropiate-like activity have been identified. Many opioidreceptor-interactive compounds including those used for producinganalgesia (e.g., morphine) and those used for treating drug addiction(e.g., naltrexone and cyclazocine) in humans have limited utility due topoor oral bioavailability and a very rapid clearance rate from the body.This has been shown in many instances to be due to the presence of the8-hydroxyl group (OH) of 2,6-methano-3-benzazocines, also known asbenzomorphans [(e.g., cyclazocine and EKC (ethylketocyclazocine)] andthe corresponding 3-OH group in morphinanes (e.g., morphine).

The high polarity of these hydroxyl groups retards oral absorption ofthe parent molecules. Furthermore, the 8-(or 3-)OH group is prone tosulfonation and glucuronidation (Phase II metabolism), both of whichfacilitate rapid excretion of the active compounds, leading todisadvantageously short half-lives for the active compounds.Unfortunately, the uniform experience in the art of the past seventyyears has been that removal or replacement of the 8-(or 3-) OH group haslead to pharmacologically inactive compounds.

SUMMARY OF THE INVENTION

We have now found that the 8-(or 3-)hydroxyl group may be replaced by anumber of small, polar, neutral residues, such as carboxamide,thiocarboxamide, hydroxyamidine and formamide groups. Not only do thebenzomorphan, morphinan carboxamides have unexpectedly high affinity foropioid receptors, compounds containing these groups in place of OH arefar less susceptible to Phase II metabolism and are generally moreorally bioavailable. The compounds of the invention are therefore usefulas analgesics, anti-pruritics, anti-diarrheal agents, anticonvulsants,antitussives, anorexics and as treatments for hyperalgesia, drugaddiction, respiratory depression, dyskinesia, pain (includingneuropathic pain), irritable bowel syndrome and gastrointestinalmotility disorders. Drug addiction, as used herein, includes alcohol andnicotine addiction. There is evidence in the literature that thecompounds may also be useful as immunosuppressants andantiinflammatories and for reducing ischemic damage (andcardioprotection), for improving learning and memory, and for treatingurinary incontinence.

In one aspect, the invention relates to2,6-methano-3-benzazocine-8-carboxamides and2,6-methano-3-benzazocine-8-carboxylate esters of formula:

wherein

-   A is chosen from —CH₂-Z, —CN, —NHSO₂-(loweralkyl),

-   Q is chosen from O, S and NR¹⁷;-   Y is chosen from O, S, NR¹⁷ and NOH;-   Z is chosen from OH, SH, CN and NH₂;-   R¹ is chosen from hydrogen, lower alkoxy, phenyl and —NHR⁸;-   R² and R^(2a) are both hydrogen or taken together R² and R^(2a) are    ═O;-   R³ is chosen from hydrogen, lower alkyl, alkenyl, aryl,    heterocyclyl, benzyl and hydroxyalkyl;-   R⁴ is chosen from hydrogen, hydroxy, amino, lower alkoxy, C₁-C₂₀    alkyl and C₁-C₂₀ alkyl substituted with hydroxy or carbonyl;-   R⁵ is lower alkyl;-   R⁶ is lower alkyl;-   R⁷ is chosen from hydrogen and hydroxy; or    together R⁴, R⁵, R⁶ and R⁷ may form from one to three rings, said    rings having optional additional substitution;-   R⁸ is chosen from hydrogen, —OH, —NH₂ and —CH₂R¹⁵;-   R¹⁵ is chosen from hydrogen, alkyl, aryl, substituted aryl and alkyl    substituted with alkoxy, amino, alkylamino or dialkylamino;-   R¹⁶ is chosen from hydrogen and NH₂; and-   R¹⁷ is chosen from hydrogen, alkyl, aryl and benzyl;    with the provisos that, (1) when R² and R^(2a) are hydrogen, R³ is    hydrogen or cyclopropyl, R⁴ is hydroxy, and together R⁵, R⁶ and R⁷    form two rings substituted with a spirodioxolane, A cannot be    —COOCH₃ or NHSO₂CH₃; (2) when R² and R^(2a) are hydrogen, R³ is    hydrogen or cyclopropyl, R⁴ is hydroxy, and together R⁵, R⁶ and R⁷    form the ring system of oxymorphone and naltrexone, A cannot be    NHSO₂CH₃; (3) when R², R^(2a), R⁴ and R⁷ are hydrogen, R³ is    cyclopropyl and R⁵ and R⁶ are methyl, A cannot be —NHC(O)H. The    explicit provisos exclude oxymorphone and naltrexone-3-sulfonamides,    which were disclosed as having no activity in vitro or in vivo    [McCurdy et al. Org. Lett. 2, 819-821 (2000)]; and cyclazocine    formamide, which was disclosed as an intermediate in a synthesis in    U.S. Pat. Nos. 3,957,793; 4,032,529 and 4,205,171. Additionally,    when A is —CN, R⁷ must be hydroxyl.

Subclasses of the foregoing structure include:

-   II. 2,6-methano-3-benzazocines of the structure shown above, in    which R⁴, R⁵, R⁶ and R⁷ do not form additional rings;-   III. morphinans in which R⁵ and R⁶ form one ring:

-   IV. morphinans in which R⁵, R⁶ and R⁷ form two rings:

and

-   V. morphinans wherein R⁴ and R¹¹ form an additional sixth ring,    which may be saturated or unsaturated:

or

In addition to the major subclasses, there are compounds such as

which the person of skill recognizes as closely related to the majorsubclasses, but which defy easy description in a common Markushstructure.

In another aspect, the invention relates to a method for preparing asecond compound that interacts with an opioid receptor when a firstcompound that interacts with an opioid receptor is known. When the firstcompound contains a phenolic hydroxyl, the method comprises convertingthe phenolic hydroxyl to a residue chosen from the group described asthe variable A above.

In another aspect, the invention relates to a method for decreasing therate of metabolism of a compound that interacts at an opioid receptor.When the first compound contains a phenolic hydroxyl, the methodcomprises converting the phenolic hydroxyl to a residue chosen from thegroup described as the variable A above.

In another aspect, the invention relates to methods for inhibiting,eliciting or enhancing responses mediated by an opioid receptorcomprising:

-   (a) providing a first compound that inhibits, elicits or enhances an    opioid receptor response;-   (b) preparing a second compound that interacts with an opioid    receptor by converting a phenolic hydroxyl group on the first    compound to a residue described as A above; and-   (c) bringing the second compound into contact with the opioid    receptor.

In another aspect, the invention relates to a method for treating adisease by altering a response mediated by an opioid receptor. Themethod comprises bringing into contact with the opioid receptor acompound having the formula

wherein B represents the appropriate residue of a known compound offormula

and the known compound of that formula alters a response mediated by anopioid receptor.

In another aspect, the invention relates to processes for convertingopioid-binding phenols or phenols on a benzomorphan or morphinane to acarboxamide. The carboxamide conversion processes comprise either:

-   (a) reacting the phenol with a reagent to convert it to a group    displaceable by CN^(θ);-   (b) reacting that group with Zn(CN)₂ in the presence of a Pd(0)    catalyst to provide a nitrile; and-   (c) hydrolyzing the nitrile to a carboxamide; or:-   (a) reacting the phenol with a reagent to convert the phenol to a    triflate;-   (b) reacting the triflate with carbon monoxide and ammonia in the    presence of a Pd(II) salt and a Pd(0) catalyst to provide a    carboxamide; or-   (a) reacting the phenol with a reagent to convert the phenol to a    triflate;-   (b) reacting the triflate with carbon monoxide and    hexamethyldisilazane in the presence of a Pd(II) salt and a Pd(0)    catalyst to provide a silylated carboxamide precursor; and-   (c) hydrolyzing the silylated carboxamide precursor to provide a    carboxamide.

Similar processes convert phenols to amidines and thioamides by reactingthe foregoing nitrile with hydroxylamine to produce a hydroxyamidine orreacting the foregoing carboxamide with a pentavalent phosphorus-sulfurreagent to produce a thioamide. For the purpose of the invention an“opioid-binding phenol” is one that exhibits binding at an opioidreceptor below 25 nM.

DETAILED DESCRIPTION OF THE INVENTION

From many years of SAR studies, it is known that the hydroxyl ofmorphinans and benzomorphans interacts with a specific site in theopiate receptor. Previous exploration of the tolerance of this site forfunctional groups other than phenolic hydroxyls has almost uniformlyresulted in the complete or near-complete loss of opioid binding. Wehave now surprisingly found that the hydroxyl can be replaced with oneof several bioisosteres. Although a fairly wide range of primary andsecondary carboxamides, as well as carboxylates, aminomethyl,hydroxymethyl and even dihydroimidazolyl exhibit binding in the desiredrange below 25 nanomolar, optimal activity is observed with acarboxamido, thiocarboxamido, hydroxyamidino or formamido group.

Since the hydroxyl functionality of benzomorphans and morphinans can bechemically converted to an amide by a simple, flexible and convenientroute described below, and since thiocarboxamido, hydroxyamidino andformamido compounds are also easily synthesized as described below, thedoor is opened to improving the bioavailability of virtually any of theknown and new therapeutic agents that rely on opioid binding for theiractivity. Moreover, since the receptor seems to tolerate some variationbeyond the α-carbon of A, one may contemplate further modulatingreceptor specificity, affinity and tissue distribution by varying theproperties of the alkyl or aryl substituents on A. Preferred residues Aare —COOCH₃, —COOEt, —CONH₂, —C(═S)NH₂, —C(O)NHOH, —C(O)NHNH₂, —CONHCH₃,—CONHBn, —CONHCH₂(4-MeOC₆H₄), 2-(4,5-dihydroimidazolyl), —C(═NOH)NH₂,—CH₂NH₂, CH₂OH, —COC₆H₅, —C(═NOH)C₆H₅, —NHCHO, —NHCHS and —NHSO₂CH₃.When R⁷ is hydroxyl, A may also be —CN. Most preferred are —CONH₂,—C(═S)NH₂, —C(═NOH)NH₂, and —NHCHO.

It is known in the art that compounds that are μ, δ and κ agonistsexhibit analgesic activity; compounds that are selective μ agonistsexhibit anti-diarrheal activity and are useful in treating dyskinesia; μantagonists and κ agonists are useful in treating heroin, cocaine,alcohol and nicotine addiction; κ agonists are also anti-pruritic agentsand are useful in treating hyperalgesia. Recently it has been found[Peterson et al. Biochem. Pharmacol. 61, 1141-1151 (2001)] that κagonists are also useful in treating retroviral inflections. In general,the dextrorotatory isomers of morphinans of type III above are useful asantitussives and anticonvulsants.

Opioid receptor ligands having known high affinity are shown in thefollowing charts 1 and 2. Replacement of OH in these compounds producescompounds that exhibit similar activity and better bioavailability.

Other opioid receptor ligands are described in Aldrich, J. V.“Analgesics” in Burger's Medicinal Chemistry and Drug Discovery, M. E.Wolff ed., John Wiley & Sons 1996, pages 321-44, the disclosures ofwhich are incorporated herein by reference.

We have examined the opioid receptor binding of a series of analogs ofknown compounds that interact at opioid receptors in which the OH isreplaced by the R-group shown in Tables 1-4. The standards are shown inTable 5. The affinities of the compounds of the invention weredetermined in guinea pig brain cells by the method described in Wentlandet al. Biorgan. Med. Chem. Lett. 9. 183-187 (2000). Alternatively, wherenoted, the affinities of the compounds of the invention were determinedin cloned human receptors in Chinese hamster ovary cells by the methoddescribed by Xu et al [Synapse 39,

TABLE 1 Cyclazocine subseries

[³H] [³H] [³H] DAMGO Naltrindole U69,593 example A = (μ) (δ) (κ)  1 CN  540 ± 50  2700 ± 1400   71 ± 13  2 COOH   58 ± 1.8   320 ± 14   31 ±0.87  3 CO₂CH₃   45 ± 0.92   59 ± 2.1  2.0 ± 0.21  4 CONH₂  0.41 ± 0.07 8.3 ± 0.49 0.53 ± 0.06  4 CONH₂  0.32 ± 0.04 NT 0.60 ± 0.04  4CONH₂•HCl  0.34 ± 0.01  4.9 ± 0.80 0.42 ± 0.02  4a (−)CONH₂  0.17 ± 0.04 2.6 ± 0.6 0.28 ± 0.01  4b (+)CONH₂   63 ± 5.4   570 ± 50   67 ± 1.6  5C(═S)NH₂  0.22 ± 0.02  4.0 ± 0.48 0.67 ± 0.01  6 CONHOH   12 ± 0.32  210 ± 40  6.9 ± 0.61  7 CONHNH₂   60 ± 9.3   450 ± ∀ 62   19 ± 1.4  8CONHCH₃   24 ± 1.6   63 ± 4.1  2.6 ± 0.19  9 CONHCH₂C₆H₅   20 ± 2.2  140 ± 18   78 ± 7.6 10 CONHCH₂(4-MeOC₆H₄)   19 ± 1.5   150 ± 17  110 ±3.1 11 CONHCH₂CH₂N(CH₃)₂   26 ± 2.9   350 ± 51   44 ± 11 12CONH(CH₂)₃N(CH₃)₂   370 ± 54  3000 ± 230 310 ± 64 132-(4,5-H₂)-imidazolyl   23 ± 1.9   55 ± 5.1   11 ± 0.69 14 C(═NOH)NH₂ 3.8 ± 0.42   16 ± 0.67 0.90 ± 0.15 15 CH₂NH₂   31 ± 5.4   390 ± 47   17± 2.9 16 CH₂OH   21 ± 2.0   210 ± 29  7.6 ± 0.80 17 COC₆H₅   33 ± 0.90  490 ± 43   19 ± 2.6 18 C(═NOH)C₆H₅   86 ± 3.8   180 ± 15  7.2 ± 0.4038 CH₂CN  3.3 ± 1.5 ^(a)  2000 ± 685 ^(a)  2.9 ± 0.36 ^(a) 39 CH(N═OH)  18 ± 1.8 ^(a)   140 ± 15 ^(a) 0.73 ± 0.03 ^(a) 19 NHCHO  1.9 ± 0.14  37 ± 3.9 0.85 ± 0.080 19a (−)NHCHO  1.1 ± 0.04  9.8 ± 0.28 0.49 ±0.012 19b (+)NHCHO  2300 ± 180 >10,000  900 ± 8.7 20 NHCHS  0.76 ± 0.09  16 ± 0.30 0.63 ± 0.15 21 NHSO₂CH₃   15 ± 1.2   780 ± 170   21 ± 1.5 36NHCONH₂   20 ± 0.66   90 ± 12   15 ± 1.4 37 NHCSNH₂   10 ± 1.7 ^(a)  440 ± 72 ^(a)  4.0 ± 0.54 ^(a) ^(a) data from chinese hamster ovaryrather than guinea pig brain

TABLE 2 Keto subseries:

[³H] [³H] [³H] DAMGO Naltrindole U69,593 example A = (μ) (δ) (κ) 22 CN(KC)  680 ± 61  3400 ± 410   59 ± 0.77 23 CONH₂ (KC)  1.4 ± 0.07   20 ±2.3  1.8 ± 0.10 24 CONH₂ (EKC)  1.2 ± 0.12  9.8 ± 0.50 0.70 ± 0.08 40NHCHO (EKC)  6.1 ± 0.83   52 ± 3.4  1.2 ± 0.11

TABLE 3 Merz subseries

[³H] [³H] [³H] DAMGO Naltrindole U69,593 example A = (μ) (δ) (κ) 25(−)-(2″S)-8-OH  0.19 ± 0.01  3.6 ± 0.40  0.09 ± 0.01 26(−)-(2″S)-8-CONH₂ 0.052 ± 0.013  2.0 ± 0.15 0.089 ± 0.004 27(−)-(2″R)-8-OH  4.0 ± 0.54   67 ± 4.3  1.5 ± 0.07 28 (−)-(2″R)-8-CONH₂ 2.9 ± 0.17   34 ± 0.10  2.8 ± 0.24 29 (−)-(2″S)-8-CH₂NH₂   28 ± 2.3 300 ± 27   18 ± 1.9

TABLE 4 Other Series

[³H] [³H] [³H] DAMGO Naltrindole U69,593 example A = (μ) (δ) (κ) 30CONH₂ (morphine)   34 ± 1.8  1900 ± 81  2000 ± 97 31 CONHCH₃ (morphine) 440 ± 9.2 >10,000 >10,000 32 CONH₂ (naltrexone)  1.9 ± 0.21   110 ± 8.1  22 ± 0.85 33 CO₂Et (naltrexone)   24 ± 1.7   970 ± 155   16 ± 0.70 41(−) NHCHO (naltrexone)  4.1 ± 0.40 ^(a)   280 ± 7.6 ^(a)  2.3 ± 0.044^(a) 34 CONH₂ (naltrindole)   47 ± 2.7  0.33 ± 0.04   99 ± 7.9 35 CONH₂(buprenorphine)  2.3 ± 0.29  7.3 ± 0.61  4.3 ± 0.05 42 CONH₂(nalbuphine)  3.8 ± 0.62 ^(a)   150 ± 82 ^(a)  0.46 ± 0.04 ^(a) 43 CN(7-OH) 0.35 ± 0.092 ^(a)   82 ± 24 ^(a)  2.6 ± 0.21 ^(a) 44 CONH2(butorphanol) 0.15 ± 0.019 ^(a)   14 ± 2.1 ^(a)  0.39 ± 0.057 ^(a)

TABLE 5 Standards [³H]Naltrindole [³H]U69,593 [³H]DAMGO (μ) (δ) (κ)(±)-Cyclazocine 0.32 ± 0.02  1.1 ± 0.04  0.18 ± 0.020 (±)-Cyclazocine  0.16 ± 0.01^(a)    2.0 ± 0.22^(a)   0.07 ± 0.01^(a) (+)-Cyclazocine360 ± 16  1100 ± 63   76 ± 8.2 (−)-Cyclazocine 0.10 ± 0.03 0.58 ± 0.060.052 ± 0.009 (±)-EKC 0.78 ± 0.10  3.4 ± 0.41 0.62 ± 0.11(±)-ketocyclazocine  3.3 ± 0.66  20 ± 2.7  1.0 ± 0.24(±)-ketocyclazocine    1.7 ± 0.21^(a) 130 ± 14^(a )    1.0 ± 0.019^(a)naltrexone (3-OH) 0.17 ± 0.03  11 ± 1.1 0.31 ± 0.03 naltrindole (3-OH) 13 ± 1.1 0.13 ± 0.02  4.6 ± 0.23 buprenorphine 0.98 ± 0.11 0.72 ± 0.100.90 ± 0.11 nalbuphine    1.6 ± 0.37^(a) 580 ± 80^(a )    3.0 ± 0.63^(a)butorphanol    0.12 ± 0.058^(a)    12 ± 3.8^(a)    0.22 ± 0.023^(a)Example 4 was tested several times independently to confirm the K_(i)'s.Inspection of the results in Table 1 indicates not only that affinity ispreserved in the compounds of the invention, but also that receptorselectivity can be modulated.

Antinociceptive activity is evaluated by the method described in Jianget al. [J. Pharmacol. Exp. Ther. 264, 1021-1027 (1993), page 1022].Compound 4 was found to exhibit an ED₅₀ of 0.21 nmol in the mouse aceticacid writhing test when administered i.c.v. Its “parent” cyclazocineexhibited an ED₅₀ of 2.9 nmol i.c.v. The time courses in producingantinociception in the mouse writhing test were compared for compound 4and cyclazocine. Mice were injected with 1.0 mg/kg of either compound 4or cyclazocine, given by i.p. administration. An increase in theduration of action from ca. 2 hr to 15 hr was observed for compound 4compared to cyclazocine.

Definitions

Throughout this specification the terms and substituents retain theirdefinitions.

Alkyl is intended to include linear, branched, or cyclic hydrocarbonstructures and combinations thereof. Lower alkyl refers to alkyl groupsof from 1 to 6 carbon atoms. Examples of lower alkyl groups includemethyl, ethyl, propyl, isopropyl, cyclopropyl, butyl, s- and t-butyl,cyclobutyl and the like. Preferred alkyl groups are those of C₂₀ orbelow. Cycloalkyl is a subset of alkyl and includes cyclic hydrocarbongroups of from 3 to 8 carbon atoms. Examples of cycloalkyl groupsinclude c-propyl, c-butyl, c-pentyl, norbornyl and the like.

Alkoxy or alkoxyl refers to groups of from 1 to 8 carbon atoms of astraight, branched, cyclic configuration and combinations thereofattached to the parent structure through an oxygen. Examples includemethoxy, ethoxy, propoxy, isopropoxy, cyclopropyloxy, cyclohexyloxy andthe like. Lower-alkoxy refers to groups containing one to four carbons.

Aryl and heteroaryl mean a 5- or 6-membered aromatic or heteroaromaticring containing 0-3 heteroatoms selected from O, N, or S; a bicyclic 9-or 10-membered aromatic or heteroaromatic ring system containing 0-3heteroatoms selected from O, N, or S; or a tricyclic 13- or 14-memberedaromatic or heteroaromatic ring system containing 0-3 heteroatomsselected from O, N, or S. The aromatic 6- to 14-membered carbocyclicrings include, e.g, benzene, naphthalene, indane, tetralin, and fluoreneand the 5- to 10-membered aromatic heterocyclic rings include, e.g.,imidazole, pyridine, indole, thiophene, benzopyranone, thiazole, furan,benzimidazole, quinoline, isoquinoline, quinoxaline, pyrimidine,pyrazine, tetrazole and pyrazole.

Arylalkyl means an alkyl residue attached to an aryl ring. Examples arebenzyl, phenethyl and the like. Heteroarylalkyl means an alkyl residueattached to a heteroaryl ring. Examples include, e.g., pyridinylmethyl,pyrimidinylethyl and the like.

Heterocycle means a cycloalkyl or aryl residue in which one to two ofthe carbons is replaced by a heteroatom such as oxygen, nitrogen orsulfur. Heteroaryls form a subset of heterocycles. Examples ofheterocycles that fall within the scope of the invention includepyrrolidine, pyrazole, pyrrole, indole, quinoline, isoquinoline,tetrahydroisoquinoline, benzofuran, benzodioxan, benzodioxole (commonlyreferred to as methylenedioxyphenyl, when occurring as a substituent),tetrazole, morpholine, thiazole, pyridine, pyridazine, pyrimidine,thiophene, furan, oxazole, oxazoline, isoxazole, dioxane,tetrahydrofuran and the like.

Substituted alkyl, aryl, cycloalkyl, or heterocyclyl refer to alkyl,aryl, cycloalkyl, or heterocyclyl wherein up to three H atoms in eachresidue are replaced with halogen, hydroxy, loweralkoxy, carboxy,carboalkoxy, carboxamido, cyano, carbonyl, —NO₂, —NR¹R²; alkylthio,sulfoxide, sulfone, acylamino, amidino, phenyl, benzyl, heteroaryl,phenoxy, benzyloxy, heteroaryloxy, or substituted phenyl, benzyl,heteroaryl, phenoxy, benzyloxy, or heteroaryloxy.

Virtually all of the compounds described herein contain one or moreasymmetric centers and may thus give rise to enantiomers, diastereomers,and other stereoisomeric forms that may be defined, in terms of absolutestereochemistry, as (R)- or (S)-. The present invention is meant toinclude all such possible isomers, as well as their racemic andoptically pure forms. In general it has been found that the levo isomerof morphinans and benzomorphans is the more potent antinociceptiveagent, while the dextro isomer may be useful as an antitussive orantispasmodic agent. Optically active (R)- and (S)-isomers may beprepared using chiral synthons or chiral reagents, or resolved usingconventional techniques. When the compounds described herein containolefinic double bonds or other centers of geometric asymmetry, andunless specified otherwise, it is intended that the compounds includeboth E and Z geometric isomers. Likewise, all tautomeric forms are alsointended to be included.

Abbreviations The following abbreviations and terms have the indicatedmeanings throughout: Ac = acetyl BNB = 4-bromomethyl-3-nitrobenzoic acidBoc = t-butyloxy carbonyl Bu = butyl c- = cyclo DAMGO =Tyr-ala-Gly-NMePhe-NHCH₂OH DBU = diazabicyclo[5.4.0]undec-7-ene DCM =dichloromethane = methylene chloride = CH₂Cl₂ DEAD = diethylazodicarboxylate DIC = diisopropylcarbodiimide DIEA =N,N-diisopropylethyl amine DMAP = 4-N,N-dimethylaminopyridine DMF =N,N-dimethylformamide DMSO = dimethyl sulfoxide DPPF =1,1′-bis(diphenylphosphino)ferrocene DVB = 1,4-divinylbenzene EEDQ =2-ethoxy-1-ethoxycarbonyl-1,2-dihydroquinoline Fmoc =9-fluorenylmethoxycarbonyl GC = gas chromatography HATU =O-(7-Azabenzotriazol-1-yl)-1,1,3,3-tetramethyluroniumhexafluorophosphate HOAc = acetic acid HOBt = hydroxybenzotriazole Me =methyl mesyl = methanesulfonyl MTBE = methyl t-butyl ether NMO =N-methylmorpholine oxide PEG = polyethylene glycol Ph = phenyl PhOH =phenol PfP = pentafluorophenol PPTS = pyridinium p-toluenesulfonatePyBroP = bromo-tris-pyrrolidino-phosphonium hexafluorophosphate rt =room temperature sat'd = saturated s- = secondary t- = tertiary TBDMS =t-butyldimethylsilyl TFA = trifluoroacetic acid THF = tetrahydrofuranTMOF = trimethyl orthoformate TMS = trimethylsilyl tosyl =p-toluenesulfonyl Trt = triphenylmethyl

In the general processes described below, the preferred reagent toconvert a phenol to a group displaceable by CN^(θ) istrifluoromethansulfonic anhydride, which is usually employed in thepresence of base. Other reagents are known to persons of skill in theart to convert phenols to groups that may be displaced by cyanide anion.The advantage of the trifluoromethansulfonic anhydride procedure is thatit allows displacement under conditions that are mild enough to avoiddestruction of the rest of the molecule for most species of interest.Other reagents are operable, but require more robust substrates than maybe of interest in a particular case. The consideration of which to useis within the skill of the artisan. A preferred Pd(0) catalyst for usein the displacement with zinc cyanide istetrakis(triphenylphosphine)palladium. In the direct displacements withcarbon monoxide and ammonia or an ammonia equivalent, the preferredPd(0) catalyst is generated in situ from Pd(OAc)₂ or PdCl₂ and1,1′-bis(diphenylphosphino)ferrocene. Other Pd(0) ligands include DPPF,DPPP, triphenylphosphine, 1,3-bis(diphenylphosphino)propane, BINAP andxantphos. The preferred pentavalent phosphorus-sulfur reagents forconverting carboxamides to thiocarboxamides are Lawesson's reagent andphosphorus pentasulfide.

It may happen that residues in the substrate of interest requireprotection and deprotection during the conversion of the phenol to thedesired bioisostere. Terminology related to “protecting”, “deprotecting”and “protected” functionalities occurs throughout this application. Suchterminology is well understood by persons of skill in the art and isused in the context of processes which involve sequential treatment witha series of reagents. In that context, a protecting group refers to agroup which is used to mask a functionality during a process step inwhich it would otherwise react, but in which reaction is undesirable.The protecting group prevents reaction at that step, but may besubsequently removed to expose the original functionality. The removalor “deprotection” occurs after the completion of the reaction orreactions in which the functionality would interfere. Thus, when asequence of reagents is specified, as it is in the processes of theinvention, the person of ordinary skill can readily envision thosegroups that would be suitable as “protecting groups”. Suitable groupsfor that purpose are discussed in standard textbooks in the field ofchemistry, such as Protective Groups in Organic Synthesis by T. W.Greene [John Wiley & Sons, New York, 1991], which is incorporated hereinby reference.

The compounds of the invention are synthesized by one of the routesdescribed below:

Chemical Syntheses

Proton NMR [Varian Unity-500 (500 MHz) NMR] data, direct insertion probe(DIP) chemical ionization mass spectra (Shimadzu GC-17A GC-MS massspectrometer), and infrared spectra (Perkin-Elmer Paragon 1000 FT-IRspectrophotometer) were consistent with the assigned structures of alltest compounds and intermediates. ¹H NMR multiplicity data are denotedby s (singlet), d (doublet), t (triplet), q (quartet), m (multiplet),and br (broad). Coupling constants are in hertz. Carbon, hydrogen, andnitrogen elemental analyses for all novel targets were performed byQuantitative Technologies Inc., whitehouse, N.J., and were within ±0.4%of theoretical values except as noted; the presence of water wasconformed by proton NMR. Melting points were determined on a Meltempcapillary melting point apparatus and are uncorrected. Optical rotationdata were obtained from a Perkin-Elmer 241 polarimeter. Reactions weregenerally performed under a N₂ atmosphere. Amines used in thePd-catalyzed amination reactions andracemic-2,2′-bis(diphenylphosphino)-1,1′-binapthyl (BINAP) werepurchased from Aldrich Chemical Company and used as received unlessotherwise indicated. Tris(dibenzylideneacetone) dipalladium (0)[Pd₂(dba)₃], Pd(OAc)₂, 1,1′-bis(diphenylphosphino)ferrocene (DPPF), werepurchased from Strem Chemicals, Incorporated. Toluene and Et₂O weredistilled from sodium metal. THF was distilled from sodiumibenzophenoneketyl. Pyridine was distilled from KOH. Methylene chloride was distilledfrom CaH₂. DMF and DMSO were distilled from CaH₂ under reduced pressure.Methanol was dried over 3±molecular sieves prior to use. Silica gel(Bodman Industries, ICN SiliTech 2-63 D 60A, 230-400 Mesh) was used forflash column chromatography.

(±)-3-(Cyclopropylmethyl)-1,2,3,4,5,6-hexahydro-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-carbonitrile[1]. The triflate [36] of cyclazocine [35] (470 mg, 1.166 mmol),obtained by the method of Wentland et al. [Bioorgan. Med. Chem. Lett. 9,183-187 (2000)], was dissolved in 20 mL DMF and Zn(CN)₂ (272.6 mg, 2.322mmol) and Pd(PPh₃)₄ (53.9 mg, 0.0466 mmol) were added. After heating in120° C. for 2 h, the reaction was allowed to stir at 25° C. overnight. Amixture of EtOAc and NaHCO₃ solution was then added. The organic phasewas washed with brine and then dried over anhydrous Na₂SO₄, filtered andconcentrated in vacuo to dryness. Flash column chromatography gave 1 asa colorless oil (260 mg, 80%). ¹H-NMR (500 MHz, CDCl₃) d 7.52 (b, 1H),7.37 (dd, J=7.8, 1.5 Hz, 1H), 7.14 (d, J=8.1, 1H), 3.15 (m, 1H), 2.96(d, J=19.0 Hz, 1H), 2.66-2.74 (m, 2H), 2.45 (m, 1H), 2.30 (m, 1H),1.84-1.98 (m, 3H), 1.38 (s, 3H), 1.29 (m, 1H), 0.85 (m, 1H), 0.82 (d,J=7.1 Hz, 3H), 0.51 (m, 2H), 0.10 (m, 2H). IR (film) 2961, 2918, 2225cm⁻¹. CI-MS, m/z (relative intensity) 281 (M+1, 100%). Anal. Calcd. forC₁₉H₂₄N₂.0.125H₂O: C, 80.78; H, 8.59; N, 9.92. Found: C, 80.75; H, 8.63;N, 9.89.

(±)-3-(Cyclopropylmethyl)-1,2,3,4,5,6-hexahydro-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-carboxamide[4]. Compound 1 (80 mg, 0.286 mmol) was dissolved in about niL t-butylalcohol. KOH (58.8 mg, 1.05 mmol) was then added. The reaction mixturewas stirred at reflux for about 20 min and the solvent was evaporatedand CH₂Cl₂ and MeOH and NaCl solution were added. The organic phase waswashed with brine and then dried over anhydrous Na₂SO₄, filtered andconcentrated in vacuo to dryness to give 4 as white foam (80 mg, 95%).¹H-NMR (500 MHz, CD₃OD) d 7.81 (m, 1H), 7.62 (m, 1H), 7.17 (m, 1H), 3.22(m, 1H), 3.04 (m, 1H), 2.66-2.82 (m, 2H), 2.50 (m, 1H), 2.35 (m, 1H),1.86-1.98 (m, 3H), 1.34 (s, 3H), 1.36 (m, 1H), 0.88 (m, 1H), 0.84 (d,J=7.0 Hz, 3H), 0.54 (m, 2H), 0.16 (m, 2H) ¹³C-NMR (500 MHz, CD₃OD) d172.71, 143.32, 142.34, 133.01, 128.61, 126.61, 126.18, 60.67, 58.09,46.92, 42.74, 42.38, 37.69, 25.92, 25.07, 14.62, 9.67, 4.64, 4.52. IR(film) 1654.2 cm⁻¹. CI-MS, m/z (relative intensity) 299 (M+1, 100%).Anal. Calcd. for C₁₉H₂₆N₂.0.0.25H₂O: C, 75.37; H, 8.76; N, 9.26. Found:C, 75.27; H, 9.02; N, 9.03.

(±)-3-(Cyclopropylmethyl)-1,2,3,4,5,6-hexahydro-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-carboxamide[1] (alternate procedure). A flask containing triflate 36 (100 mg),Pd(OAc)₂ (10.2 mg), and 1,1′-bis(diphenylphosphino)ferrocene(DPPF, 25mg) was purged with argon. The argon was replaced with gaseous CO andthe reaction vessel was closed to the atmosphere. Dry DMSO (1.25 mL) wasadded via syringe and gaseous ammonia was added to the resulting mixturevia a canula. A balloon was used to keep the additional volumecontained. The mixture was stirred for 17 h at 70° C. followed bycooling to 25° C. The reaction mixture was diluted with water and theproduct was extracted into ethyl acetate. The organic extracts waswashed with aqueous NaHCO₃ and dried (Na₂SO₄). Concentration of thesolvent in vacuo gave 90 mg of a crude product. This material waspurified via flash chromatography (25:1:0.1-CH₂Cl₂:MeOH: conc NH₄OH) toprovide 47 mg (65.3%) of compound 4.

(±)-3-(Cyclopropylmethyl)-1,2,3,4,5,6,-hexahydro-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-carboxylicacid methyl ester [3]. A modification of a known procedure (Cacchi, S.;Ciattini, P. G.; Morera, E.; Ortar, G. Tetrahedron Lett. 1986, 27,3931-3934) was used in this preparation. Under an argon atmosphere,triethylamine (0.30 mL, 2.15 mmol) was added to a mixture of the8-triflate ester of cyclazocine [36] (0.403 g, 1.0 mmol), palladiumacetate (0.0068 g, 0.03 mmol), 1, 1′-bis(diphenylphosphino)ferrocene(0.00166 g, 0.03 mmol) and methanol (1 mL, 22.2 mmol) in DMF (1 mL). Thesolution was purged with carbon monoxide for 15 min and stirred under aCO balloon at 70° C. for 5 h. The reaction mixture was taken up in 20 mLof ethyl acetate and washed with saturated sodium bicarbonate solutionand water. The organic phase was dried with sodium sulfate andevaporated to give crude product as a brown oil. Chromatography onsilica gel using CH₂Cl₂:MeOH:NH₄OH (conc)/40:1:0.1 provided the desiredcompound 3 (0.235 g, 86.6%) as a colorless oil: ¹H NMR (500 MHz, CDCl₃)δ 7.93 (d, J=1.7 Hz, 1H), 7.76 (dd, J=1.7 Hz, J₂=7.8 Hz, 1H), 7.12 (d,J=7.8 Hz, 1H), 3.89 (s, 3H), 3.15 (m, 1H), 2.96 (d, J=19.0 Hz, 1H), 2.73(d, J=6.1 Hz, 1H), 2.70 (m, 1H), 2.46 (dd, J₁=7.3 Hz, J₂=12.4 Hz, 1H),2.31 (dd, J₁=6.6 Hz, J₂=12.4 Hz, 1H), 1.96 (m, 1H), 1.91 (m, 2H), 1.43(s, 3H), 1.33 (m, 1H), 0.86 (m, 1H), 0.83 (d, J=7.1 Hz, 3H), 0.51 (d,J=8.1 Hz, 2H), 0.11 (m, 2H); IR (film) ν_(max) 2916, 1720, 1270 cm⁻¹; MS(CI) m/z 314 (M+H)⁺; Anal. calc. for C₂₀H₂₇NO₂: C, 76.64; H, 8.68; N,4.47. Found: C, 76.37; H, 8.93; N, 4.38.

(±)-[3-(Cyclopropylmethyl)-1,2,3,4,5,6,-hexahydro-cis-6,1′-dimethyl-2,6-methano-3-benzazocin-8-yl]-methanol[1,6]. Under a blanket of N₂ at 0° C.,(±)-3-(cyclopropylmethyl)-1,2,3,4,5,6,-hexahydro-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-carboxylicacid methyl ester [3] (0.1062 g, 0.34 mmol), LiAlH₄ powder (0.0258 g,0.68 mmol) and dry THF (0.77 mL) were placed in a one-neck round bottomflask equipped with condenser and stir bar. The ice/water bath wasremoved and the reaction was stirred at reflux for 24 h. The mixture wascooled to 25° C. and quenched by adding water dropwise untileffervescence ceased. The mixture was then treated with 10% H₂SO₄ andstirred at 25° C. for 3 hours. The mixture then was extracted withdiethyl ether (2×) and the organic layer was dried (Na₂SO₄) and thesolvent was removed in vacuo. The crude product was purified by flashcolumn chromatography using CH₂Cl₂:MeOH/0:1 as eluent to provide thedesired product [16] (0.0557 g, 57%) as a light yellow oil: ¹H NMR (500MHz, CDCl₃) δ 7.24 (d, J=17 Hz, 1H), 7.10 (m, 1H), 7.08 (d, J=21.2 Hz,1H), 4.64 (s, 2H), 3.14 (m, 1H), 2.91 (d, J=18.5 Hz, 1H), 2.68 (m, 2H),2.47 (m, 1H), 2.31 (m, 1H), 1.92 (m, 6H), 1.34 (m, 3H), 0.84 (d, J=7.1Hz), 0.50 (m, 2H), 0.11 (m, 2H); Anal. calc. for C₁₉H₂₇NO: C, 79.95; H,9.53; N, 4.91. Found: C, 79.70; H, 9.50; N, 4.68.

(±)-3-(Cyclopropylmethyl)-1,2,3,4,5,6-hexahydro-N-hydroxy-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-carboxamidine[1,4]. A modification of a known procedure (Jendralla, H.; Seuring, B.;Herchen, J.; Kulitzscher, B.; Wunmer, J. Tetrahedron 1995, 51,12047-12068) was used in this preparation. A mixture of(±)-3-(cyclopropylmethyl)-1,2,3,4,5,6-hexahydro-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-carbonitrile[1] (0.230 g, 0.82 mmol), hydroxyamine hydrochloride (0.100 g, 1.44mmol) and triethylamine (0.30 mL, 2.15 mmol) in 1 mL of absolute ethanolwas stirred at reflux under an argon atmosphere for 5 h. The reactionmixture was concentrated in vacuo and the residue was taken up in 15 mLof CH₂Cl₂ and washed with water. The organic phase was dried (Na₂SO₄)and evaporated to give crude product. Flash column chromatography usingCH₂Cl₂:MeOH:NH₄OH (conc)/25:1:0.1 provided the desired compound 14(0.216 g, 84%) as a white foam: ¹H NMR (500 MHz, CDCl₃) δ 9.48 (br s,1H), 7.56 (d, J=1.5 Hz, 1H), 7.33 (dd, J₁=1.5 Hz, J₂=7.8 Hz, 1H), 7.08(d, J=7.8 Hz, 1H), 4.84 (s, 2H), 3.19 (m, 1H), 2.94 (d, J=18.8 Hz, 1H),2.72 (m, 2H), 2.48 (dd, J₁=6.3 Hz, J₂=12.5 Hz, 1H), 2.34 (dd, J₁=6.6 Hz,J₂=12.5 Hz, 1H), 2.01 (m, 3H), 1.42 (s, 3H), 1.34 (d, J=11.4 Hz, 1H),0.92 (m, 1H), 0.84 (d, J=6.8 Hz, 3H), 0.51 (m, 2H), 0.12 (m, 2H); IR(film) ν_(max) 3365, 2921, 1634, 1577 cm⁻¹; MS (CI) m/z 314 (M+H)⁺;Anal. calc. for C₁₉H₂₇N₃O: C, 72.81; H, 8.68; N, 13.47. Found: C, 72.96;H, 8.67; N, 13.18.

(±)-3-(Cyclopropylmethyl)-1,2,3,4,5,6-hexahydro-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-thiocarboxamide[5]. A modification of a known procedure (Varma R. S.; Kumar, D. OrganicLett. 1999, 1, 697-700) was used in this preparation. A mixture of(±)-3-(cyclopropylmethyl)-1,2,3,4,5,6-hexahydro-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-carboxamide[4] (0.0298 g, 0.1 mmol) and Lawsson's reagent (0.0320 g, 0.08 mmol) in1 mL of toluene was sealed in a glass tube under an argon atmosphere.The glass tube was put in a microwave oven and irradiated for 7 min.Additional Lawsson's reagent (0.0160 g, 0.04 mmol) was added and thereactants was allowed to be irradiated for additional 7 min. Thereaction mixture was taken up in 10 mL of CH₂Cl₂ and washed with water.The organic phase was dried with sodium sulfate and evaporated to givecrude product. Chromatography on silica gel using CH₂Cl₂:MeOH:NH₄OH(conc)/40:1:0.1 the provided desired compound 5 (0.022 g, 70.1%) as ayellow crystalline solid: mp 171-173° C.; ¹H NMR (500 MHz, CDCl₃) δ 7.78(d, J=1.9 Hz, 1H), 7.64 (brs, 1H), 7.60 (dd, J₁=1.9 Hz, J₂=8.1 Hz, 1H),7.19 (brs, 1H), 7.09 (d, J=8.1 Hz, 1H), 3.16 (m, 1H), 2.95 (d, J=19.0Hz, 1H), 2.70 (m, 2H), 2.46 (dd, J₁=6.1 Hz, J₂=12.4 Hz, 1H), 2.32 (dd,J₁=6.3 Hz, J₂=12.4 Hz, 1H), 1.92 (m, 3H), 1.43 (s, 3H), 1.34 (m, 1H),0.85 (m, 1H), 0.83 (d, J=7.1 Hz, 3H), 0.51 (m, 2H), 0.10 (m, 2H); IR(film) ν_(max) 3172, 2920, 1617, 1424 cm⁻¹; MS (CI) m/z 315 (M+H)⁺;Anal. calc. for C₁₉H₂₆N₂S0.75H₂O: C, 69.58; H, 8.45; N, 8.54. Found: C,69.54; H, 8.15; N, 8.26.

(±)-[3-(Cyclopropylmethyl)-1,2,3,4,5,6,-hexahydro-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-yl]-methylamine[1,5].(±)-3-(Cyclopropylmethyl)-1,2,3,4,5,6-hexahydro-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-carbonitrile[1] (0.154 g, 0.55 mmol) was dissolved in Et₂O (1.1 mL) to obtain a 0.5M solution. This solution was added dropwise via syringe to a vigorouslystirred solution of 1.0 M LiAlH₄ in Et₂O (1.1 mL, 1.1 mmol) at 0° C.After stirring at room temperature for 10 min, water was added dropwiseto quench the reaction. The resulting solution was then extracted withEtOAc several times and the combined EtOAc layers were dried (Na₂SO₄),and filtered. The solvent was removed in vacuo and the residue purifiedby flash column chromatography (CH₂Cl₂:MeOH:Et₃N/0:1:0.2) to yield thedesired product 15 (0.105 g, 67%) as a brown oil: ¹H NMR (500 MHz,CDCl₃) δ 7.16 (s, 1H), 7.04 (m, 2H), 3.82 (s, 2H), 3.16 (s, 1H), 2.91(d, J=8.3 Hz, 1H), 2.70 (m, 2H), 2.49 (m, 1H), 2.34 (m, 1H), 1.92 (m,5H), 1.39 (m, 4H), 0.85 (m, 4H), 0.51 (d, J=7.6 Hz, 2H), 0.11 (m, 2H);IR (film)<ν_(max) 3075, 2962, 2917, 2814, 1574, 1499, 1462, 1428, 1380,1333, 1218, 1101, 1075, 1018, 963 cm⁻¹; Anal. calc. for C₁₉H₂₈N₂O₅H₂O:C, 77.77; H, 9.96; N, 9.54. Found: C, 78.18; H, 10.17; N, 9.39.

(±)-N-[3-(Cyclopropylmethyl)-1,2,3,4,5,6,-hexahydro-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-yl]-formamide[1,9]. A modification of a known procedure (Chakrabarty, M.; Khasnobis,S.; Harigaya, Y.; Kinda, Y. Synthetic Comm. 2000, 30, 187-200.) was usedin this preparation.(±)-3-(Cyclopropylmethyl)-1,2,3,4,5,6-hexahydro-cis-6,11-dimethyl-2,6-methano-3-benzazocin-8-amine[37] (0.091 g, 0.337 mmol) was treated with 96% formic acid (20 mL) andwas heated at 100° C. for 14 h. The solution was then poured ontocrushed ice and basified with solid NaHCO₃. The organic material wasextracted into EtOAc (3×) and the extracts were washed with water anddried (Na₂SO₄). After concentration in vacuo, the crude product waspurified by flash column chromatography (CH₂Cl₂:MeOH:NH₄OH/10:1:0.05) toyield the desired product 19 as a brown oil (0.065 g, 65%): ¹H NMR (500MHz, CDCl₃) δ 8.62 (d, J=11.5 Hz, 0.5H, CHO of one rotomer), 8.34 (d,J=1.7 Hz, 0.5H, CHO of other rotomer), 8.17 (d, J=10.5 Hz, 0.5H, NH ofone rotomer), 7.57 (br s, 0.5H, NH of other rotomer), 7.36 (m, 1H), 7.04(m, 1H), 6.89 (m, 1H), 3.15 (m, 1H), 2.90 (m, 1H), 2.72 (m, 2H), 2.47(m, 1H), 2.32 (m, 1H), 1.95 (m, 3H), 1.32 (m, 4H), 0.85 (m, 4H), 0.51(m, 2H), 0.11 (m, 2H); IR (film) ν_(max) 3265, 2963, 2922, 1694, 1682,1614, 1538, 1503, 1462, 1402, 1380, 1311, 1218, 1100, 1074, 1020, 964,888, 808 cm⁻¹; MS (CI) m/z 299 (M+H)⁺; Anal. calc. for C₁₉H₂₆N₂O.0.125H₂O: C, 75.90; H, 8.88; N, 9.32. Found: C, 76.00; H, 8.95; N, 9.13.

The remaining compounds of Table 1 were prepared in similar fashion,except Example 8, which was made by the CO/palladium route, but with aslight variation using 2.0 M CH₃NH₂ in THF, rather than gaseous CH₃NH₂,and DMF rather than DMSO; mp=155-156° C.; 25.6% yield. 24-[the(±)-8-CONH₂ analogue of ethylketocyclazocine (R² and R^(2a)═O; R⁶=Et)]was made by the nitrile hydrolysis route, mp=194-196° C.; Step 1-89.1%,Step 2-81.4%. 23-[the (±)-8-CONH₂ analogue of ketocyclazocine (R² andR^(2a)=O; R⁶=Me)] was made by the nitrile hydrolysis route, mp=206-207°C.; Step 1-99.7%, Step 2-94.2%. It was also made by the CO/Pd route in34.7% yield.

In general, the chemistry described above works in the presence of thevariety of functional groups found on known core structures. Theexceptions would be morphine and congeners having a free 6-OH, which canbe protected by a TBDPS (t-butyldiphenylsilyl) group [see Wentland et alJ. Med. Chem. 43, 3558-3565 (2000)].

The compound identified as Example 43 in table 4 was prepared bytreating the nitrile of nalbuphine with an excess of potassium hydroxidein t-butanol as described for example 4 above. Hydrolysis of the nitrileappears to have proceeded more slowly than elimination and ring opening.

Although this invention is susceptible to embodiment in many differentforms, preferred embodiments of the invention are shown. It should beunderstood, however, that the present disclosure is to be considered asan exemplification of the principles of this invention and is notintended to limit the invention to the embodiments illustrated. It maybe found upon examination that certain members of the claimed genus arenot patentable to the inventors in this application. In this event,subsequent exclusions of species from the compass of applicants' claimsare to be considered artifacts of patent prosecution and not reflectiveof the inventors' concept or description of their invention; theinvention encompasses all of the members of the genus I that are notalready in the possession of the public.

1. A compound of formula I:

wherein, A is

Y is chosen from O, S, NR¹⁷ and NOH; R¹ is —NHR⁸; R² and R^(2a) are bothhydrogen or taken together R² and R^(2a) are ═O; R³ is chosen fromhydrogen, lower alkyl, alkenyl, aryl, benzyl and hydroxyalkyl; R⁴ ischosen from hydrogen, hydroxyl, amino, lower alkoxy, C₁-C₂₀ alkyl andC₁-C₂₀ alkyl substituted with hydroxyl or carbonyl; R⁷ is chosen fromhydrogen and hydroxyl; R⁵ is a lower alkyl ; R⁶ is a lower alkyl;wherein together R⁵ and R⁶ form one ring, said ring having optionaladditional substitution; R⁸ is chosen from hydrogen, —OH, —NH₂ and—CH₂R¹⁵; R¹⁵ is chosen from hydrogen, alkyl, aryl, substituted aryl andalkyl substituted with alkoxy, amino, alkylamino and dialkylamino; andR¹⁷ is chosen from hydrogen, alkyl, aryl and benzyl.
 2. A compound ofclaim 1 wherein A is chosen from: —CONH₂, —C(═S)NH₂, —C(O)NHOH,—C(O)NHNH₂, —CONHCH₃, —CONHBn, —CONHCH₂(4-MeOC₆H₄), and —C(═NOH)NH₂. 3.A compound of claim 2 wherein A is CONH₂.
 4. A compound of claim 3wherein R⁷ is hydroxyl.
 5. A compound of claim 3 wherein R³ is loweralkyl.
 6. A compound of claim 5 wherein R³ is selected from methyl,ethyl, propyl, isopropyl, cyclopropyl, butyl, s-butyl, t-butyl andcyclobutyl.
 7. A compound of claim 3 wherein R³ is alkenyl.
 8. Acompound of claim 3 wherein A is CONH₂, R⁷ is hydroxyl and R³ iscyclopropyl.
 9. A compound according to claim 1 of formula:

wherein, A is

Y is chosen from O, S, NR¹⁷ and NOH; R¹ is —NHR⁸; R² and R^(2a) are bothhydrogen or taken together R² and R^(2a) are ═O; R³ is chosen fromhydrogen, lower alkyl, alkenyl, aryl, benzyl and hydroxyalkyl; R⁴ ischosen from hydrogen, hydroxyl, amino, lower alkoxy, C₁-C₂₀ alkyl andC₁-C₂₀ alkyl substituted with hydroxyl or carbonyl; and R¹⁷ is chosenfrom hydrogen, alkyl, aryl and benzyl.
 10. A compound of according toclaim 9 of formula:

wherein, A is selected from —CONH₂, —C(═S)NH₂, —C(O)NHOH, —C(O)NHNH₂,—CONHCH₃, —CONHBn, —CONHCH₂ (4-MeOC₆ H₄), and —C(═NOH)NH₂; R₁₉ isselected from —CH₃, —CH₂-c-C₃H₅ and —CH₂-c-C₄H₇.
 11. A compound of claim10 wherein A is —CONH₂.
 12. A compound of claim 1 of formula:

wherein, A is selected from —CONH₂, —C(═S)NH₂, —C(O)NHOH, —C(O)NHNH₂,—CONHCH₃, —CONHBn, —CONHCH₂ (4-MeOC₆ H₄), and —C(═NOH)NH₂.
 13. Acompound of claim 12 wherein A is —CONH₂.
 14. A compound according toclaim 1 having formula: